Dental chair.



Patented Mar. 6, I900.

G. SIBLEY.

o DENTAL CHAIR.

(Application fi led Feb. 5, 1897.) (No Model.) 2 Sheets-Sheet l.

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Attorney.

I n Ve n tor.

TNE NORRIS PETER: c0 PHOTO-LITHD., WASHINGTON u Patented Mar. 6, I900.

G SIBLEY DENTAL CHAIR.

(Apglication filed Feb. 5, 1897.)

2 Shaets-Sheet 2.

(No Model.)

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Attorney.

TERS co. PHOTO-UYHG" wmumomu a c FFic E.

PATENT GIDEON SIBLEY, OF PHILADELPHIA, PENNSYLVANIA.

DENTAL CHAIR.

SPECIFICATION forming part of Letters Patent No. 644,642, dated March 6, 1900.

Application filed February 5, 1897. Serial No. 622,092. (No model.)

To aZZ whom it may concern.-

Be it known that I, GIDEON SIBLEY, a citizen of the United States, residing in the city and county of Philadelphia, in the State of Pennsylvania, have invented certain new and useful Improvements in Dental Chairs, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

This invention relates to improvements in that class of chairs in which the seat or body of the chair is vertically adjusted and sustained in its positions of adjustment by means of aliquid column-such,for example,as illustrated in my pending applications,-Serial No.

' 551,507, filed June 3, 1895; Serial No. 576,452,

filed January 22,1896, and Serial No. 607,649, filed October 2, 1896. In the chairs set out in said applications there are employed a base, a telescopic seat-supporting standard, a pump, and connections intermediate the same and the standard whereby the. standard may be raised and lowered at will to effect the requisite vertical adjustments of the chair-body, together with mechanism for automatically clamping the sections of the standard in their positions of adjustment and means for releasing said mechanism preparatory to the adjustment of the chair-body.

In the constructions particularly defined in the applications Serial Nos. 576,452 and 607,649 there are employed a central telescopic lift-cylinder connected at its upper end with the chair and at its lower end with the pump, an outer telescopic guide-cylinder connectedwith the chair-body, clamp mechanism to act automatically upon the latter cylinder, and means for releasing such mechanism at predetermined intervals.

One feature of the present improvements relates to the particular construction of the central telescopic lift cylinder above referred to, whereby the sections thereof are lubricated during their adjustment and whereby they may be extended to an extremelimit.

Another feature pertains to a novel construction and arrangement of friction devices which automatically and constantly act upon the telescopic standard during the vertical adjustment of the chair-body and also when the latter has been adjusted, thereby obviating the use of the clamping and releasing mechanisms heretofore employed.

The invention also includes details of com struction respecting the above features, as will hereinafter fully appear.

In the drawings, Figure 1 is a vertical section through the base or pedestal, the cylin der rotatably mounted thereon, the extensible lift and guide cylinders, and the friction devices therefor. Fig. 2 is a horizontal section as on the line a, a of Fig. 1. Fig. 3 is an elevation of the upper portion of the rotatable cylinder and the friction devices. Fig. 4 is a transverse section as on the line b b of Fig. 1. Fig. 5 is a vertical section through the pump and release-valve mechanism.

The numeral 1 designates a cylindrical base or pedestal, 2 a cylinder rotatablyfitted thereto and headed at its lower end, and 3 a telescopic lift-cylinder comprising three sections 10, 11, and 12, whereof the largest section, 10, is affixed to the head 3 of the cylinder 2, while the central section, 12, is connected With the chair-body, whereby when said lift-cylinder is extended or contracted the chair-body is correspondingly raised or lowered. On the lower end of the section 12 is a gasket-head 24, which takes against the interior Wall of the section 11, thus not only steadying and guiding the section in its movements, but preventing the escape of the pressure-oil between the two sections. On the upper end of the outer section is screwed or otherwise secured a collar 14, that projects beyond the top of said section, the upper projecting portion having secured therein gaskets 23, that bear against the outer wall of the section 11. In the present instance there are two gaskets, between which is interposed a ring 25, (that snugly fits the section 11,) the whole being clamped in place by a screw-ring in the top of the collar. By this construction it will be seen that while the oil will be permitted to flow between the two sections 10 11, so as to lubricate the latter intits vertical movement, the gaskets at the upper end of the fixed section will prevent the overflow and leakage of the oil. It will also be seen that these upper gaskets will permit the elevation of the section 11 to an extreme height, and, further, that the collar and its gaskets may be readily applied to or removed from the section 10 for repair, &c.,

tions of the telescopic guide-cylinder.

without necessitating the removal of any of said sections.

17 designates the pump, which has communication by suitable ports with the interiors of the cylinder and pedestal, respectively, whereby when the pump-lever 18 is actuated the oil or other liquid contained in the pedestal will be drawn into the pump-cylinder 15 and forced into the section 11 in a manner to act against the central section and elevate the same and the chairbody. In this operation the central section will be separately raised until the gasket-ring at the lower end thereof impinges against the head at the upper end of the section 11, whereupon if the operation be continued the latter section will be elevated.

In the cylinder-head 9 is a duct 20, which communicates with the discharge-port of the pump. Leading from this duct to the under side of the head is a duct 30, between which and the duct 20 is a normally-closed springactuated release-valve 31. Preparatory to lowering the chair-body a lever 34, connected with the stem of this valve, is depressed, so as to open the valve, and thus permit the escape of the oil from the lift-sections, the descent of the chair-body being arrested at any predetermined position by the closing of the valve.

The construction and operation of the pump and release-valve need not be specifically described herein, as the same are fully set forth in my other pending cases above referred to.

5 and G designate the outer and inner sec- The outer section is fitted to the upper reduced portion of the cylinder 2, while the inner section is connected with the under side of the chair-body by means of a screw 6, to the end that the telescopic cylinder will travel up and down with the chair-body, and thus perform the function of steadying and guiding the latter in its vertical movements.

The means which I now employ for steadying the guide-sections in their respective positions of vertical adjustment differs from the means to the same end set out in my prior applications in that in the present construction the use of separate actuating devices to release the holding devices at predetermined intervals is obviated, the bearing and releasing actions thereof being entirely automatic.

Referring to Fig. 1, a and b are longitudinal grooves in the peripheries of the respective guide-sections, and A and B are shoes formed on or secured to blocks a b respectively, and fitted in the respective grooves. The block of the upper shoe is snugly fitted in a lateral housing or extension at at the upper end of the outer section, so as to have horizontal play therein. In the outer Wall of this housing is a set-screw a", between which and the socketed end of the block is interposed a spiral spring a the tendency of which is to force the block inward, and thus clamp the shoe in the longitudinal groove. Obviously by adjusting the screw the force of the spring will be varied, so as to exert more or less pressure on the block, as desired.

The block of the lower shoe is fitted similarly to the upper shoe in a corresponding housing I) on the contracted portion of the cylinder 2, so that the shoe will clamp the outer section to said cylinder. In this housing I) are the spring a and the adj usting-screw c therefor, all being identical in construction and operation with the corresponding parts in the upper housing.

It will of course be understood that the telescopic lifting-sections and,perforce, the guidesections are sustained in their positions of vertical adjustment by the liquid column and that therefore the function of the shoes is not to support the several sections vertically, but to exert sufficien t lateral friction on the guidesections to maintain them and their adjuncts steadily and firmly in place. The power of the springs is such that the frictional action of the shoes may be overcome not only by the pressure of the liquid column during the elevation of the chair, but also by the weight of the chair-body when such column is removed.

During each stroke of the pump to effect the elevation of the inner guide-section the latter in its movement overcomes the frictional action thereagainst of the shoe. When the inner section has been raised sufiiciently to enable a shoulder d at or near its lower end to abut against a screw or stud d near the upper end of the outer section, the latter section ,overcomin g the friction al action thereagainst of the shoe, is raised step by step by the upwardly-moving inner section. I

If it be desired to lower the chair-body, the release-treadle is depressed, thereby permitting the escape from the lift-cylinders of the supporting liquid and insuring the descent of the chair-body against the friction of the shoes. If it be desired to limit the descent of the chair-body in any predetermined position, the operator removes his foot from the treadle, thus checking the escape of the oil.

It will be observed that the sides of the grooves in the guide-sections and the coacting sides of the shoes are correspondingly beveled, so that the shoes will always act firmly against the sides of the grooves irrespective of the wear of the opposing parts, and thus not only insure the requisite frictional action, but also prevent lateral or rotary movement of the sections.

I claim-- 1. In a chair, the combination, with the base, the chair-bod y, and the telescopic guidesections connected with the latter, of a telescopic lift-cylinder comprising three sections whereof the first section is aflixed to the base and provided with an internal packing at the upper end, the second section is fitted within the first section and headed at its upper end, and the third section is engaged at its upper end with the chair-body and is provided at its lower end with a packing engaging the second section, and a pump having operative communication with the lower end of the liftcylinder, substantially as described.

2. In a chair, the combination, with the base,the chair-body,and vertical guides therefor, of a telescopic lift-cylinder comprising three sections whereof the first section is affixed to the base and provided with an internal gasket at the upper end, the second section is fitted within the first section and headed at its upper end, and the third section is engaged at its upper end with the chair-body and is provided at its lower end with a gasket engaging the second section, the packing on the first or fixed section comprisinga collar, gaskets therein, a ring intermediate said gaskets, and a screw-ring in the top of the collar, substantially as described.

3. In a chair, the combination, with the base, a chair-body and a standard comprising a series of telescopic sections, and means for vertically adjusting and supporting said sections, of a spring pressed friction device mounted on said base and engaged with the outermost section, and aspring-pressed friction device mounted on said section and engaged with the contiguous section, the pressure of said friction devices being such as to be overcome by the action of the adjusting and supporting means during the elevation of said sections, and by the weight of the chair-body when the adjusting and supporting means are thrown out of action, substantially as described.

4. In a chair, the combination, with a base or support, and a chair-body, of a verticallymovable standard therefor, means for vertically adj usting and supporting said standard, a shoe, a horizontal guide therefor, a spring tending to press said shoe against the standard, and means exteriorly of said standard for adjusting the pressure of the spring, substantially as described.

5. In a chair, the combination, with a base or support, and a chair-body, of a verticallymovable standard therefor provided with a longitudinal peripheral groove having beveled sides, a correspondingly-beveled shoe fitted to said groove, a horizontal guide for said shoe, and a spring tending to press said shoe into the groove, substantially as described.

6. In a chair, the combination, with a base or support, and a chair-body, of a verticallymovable standard therefor, a shoe bearing against the outer side of said standard, asupporting-block therefor, an exterior extension or housing in which said block is fitted and horizontally guided, a set-screw in the outer wall of said housing, and aspring interposed between said screw and the block, substantially as described.

"7. In a chair, the combination, with a base or support, and a chair-body, of an extensible lifting-cylinder, a pump, operative connections between said pump and cylinder, a normallyclosed release-valve, means for opening the same, an extensible guide-cylinder and a spring-pressed friction device nor mally engaging said latter cylinder, the pres sure of said device being such as to be overcome by the pressure of the fluid from the pump during the elevation of the standard, and by the weight of the chair-body when the release-valve is opened, substantially as de scribed.

8. In a chair, the combination with a base and a chair-body, of a series of telescopic lifting-sections operatively connected with said base and chair-body, means for elevating said sections and for permitting their descent, an outer telescopic guide-cylinder connected with the chair-body and with said base, a spring-pressed friction device mounted on said base and engaged with the outermost section of said guide-cylinder, and a spring pressed friction device mounted on said cylinder-section and engaged with the contigu= ous section, substantially as described.

In testimony whereof I have hereunto affixed my signature in the presence of two sub scribing Witnesses.

GIDEON SIBLEY. Witnesses:

ANDREW V. GROUPE, JOHN R. NOLAN. 

